溶剂同位素对晶体和电极膜中介面蛋白质电子转移的影响
Seong A Kang1, Kevin R Hoke, Brian R Crane
1Department of Chemistry and Chemical Biology, Cornell University, Ithaca, NY 14853, USA.
Journal of the American Chemical Society
|February 16, 2006
概括
氧化物 (D2O) 替代在细胞染色体c过氧化酶 (CcP) 晶体中减缓了电子转移 (ET) 动力学. 这种在晶体和薄膜研究中观察到的D2O效应归因于缓慢交换的质子或溶剂分子影响CCP-cytochrome c相互作用.
科学领域:
- 生物化学 生物化学
- 结构生物学 结构生物学
- 物理化学 物理化学
背景情况:
- 细胞染色体c过氧化酶 (CcP) 和细胞染色体c (yCc) 是细胞呼吸中的关键酶.
- 在CCP和yCc之间,电子转移 (ET) 对于它们的功能至关重要.
- 了解影响ET率的因素对于生物化学和生物物理研究至关重要.
研究的目的:
- 调查二氧化 (D2O) 替代对酵母异-1-细胞染色体c过氧化酶 (ZnCcP) 与酵母异-1-细胞染色体c (yCc) 复合物的结构和电子转移动力学的影响.
- 阐明D2O在调节蛋白质-蛋白质相互作用和电子转移通路中的作用.
主要方法:
- D2O培养的ZnCcP-yCc晶体的X射线晶体学,以确定高分辨率结构.
- 谱分析以测量电子转移 (ET) 和三重激发状态火.
- 蛋白膜电压测量用于评估电极表面的yCc膜中的ET速率.
主要成果:
- 与H2O生长的晶体相比,D2O生长的晶体衍射到更高分辨率 (1.7 Å),并表现出不同的包装.
- 两个ZnCcP分子与一个yCc结合,观察到从ZnCcP到Fe(III) yCc (k(e) = 220 s−1).
- D2O替代显著减缓了晶体中的热再组合ET和yCc薄膜中的电子转移,并观察到同位素效应.
结论:
- D2O 替代扰乱了 yCc 和 CcP 或电极膜之间的相互作用和电子转移.
- 观察到的效应归因于缓慢交换的质子或溶剂分子,导致微妙的结构变化.
- 这些发现凸显了电子转移过程对同位素环境的敏感性.
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